The present disclosure relates to image forming apparatuses and particularly relates to a technique for controlling each of mechanisms included in an image forming apparatus in response to the opening/closing of a body cover provided on the apparatus body. The image forming apparatus is configured so that a conveyance roller conveys a recording paper sheet with a drive force supplied from a motor and an image forming section forms an image on the conveyed recording paper sheet. If in this image forming apparatus a recording paper sheet is jammed in a conveyance path, i.e., a paper jam occurs, the operator opens the body cover to expose internal mechanisms and removes the recording paper sheet jammed in the conveyance path. In this case, in conjunction with the opening of the body cover, an interlock switch is turned off to shut off power supply to the motor and a power-off detecting circuit detects the power shutoff and outputs a signal indicating it to a CPU, so that the mechanisms of the image forming apparatus can be deactivated.